Comparing yourself with others on Facebook is more likely to lead to feelings of depression than making social comparisons offline.

That's one of the findings from a review of all the research on the links between social networking and depression by David Baker and Dr Guillermo Perez Algorta from Lancaster University.

They examined studies from 14 countries with 35,000 participants aged between 15 and 88.

There are among 1.8 billion people on online social networking sites worldwide, with Facebook alone having more than 1 billion active users.

Concerns over the effect on mental health led the American Academy of Pediatrics in 2011 to define "Facebook depression" as a "depression that develops when preteens and teens spend a great deal of time on social media sites, such as Facebook, and then begin to exhibit classic symptoms of depression."

The Lancaster University review of existing research found that the relationship between online social networking and depression may be very complex and associated with factors like age and gender.

In cases where there is a significant association with depression, this is because comparing yourself with others can lead to "rumination" or overthinking.

° Negative comparison with others when using Facebook was found to predict depression via increased rumination

° Frequent posting on Facebook was found to be associated with depression via rumination

However, the frequency, quality and type of online social networking is also important.

Facebook users were more at risk of depression when they:

· Felt envy triggered by observing others

· Accepted former partners as Facebook friends

· Made negative social comparisons

· Made frequent negative status updates

Gender and personality also influenced the risk, with women and people with neurotic personalities more likely to become depressed.

But the researchers stressed that online activity could also help people with depression who use it as a mental health resource and to enhance social support.